The present invention is directed to absorbent articles and in particular, personal care absorbent articles utilized to collect and retain body fluids, liquids, or exudates including, but not limited to urine, feces, menses, and wound-released fluids, such as blood or pus. In the context of such products, comfort and absorbency are two main attributes and areas of concern for the wearer. This is particularly true with child care, adult care and feminine care products such as diapers, incontinence articles, feminine hygienic pads, liners and tampons. Less so with wound care articles, paper towels and wipes, but similar needs exist for bandage materials.
In the personal care area, large portions of the absorbent capacity of absorbent articles have often been free of soiling at the time of product disposal, thereby depriving consumers of the full value of these products. Such inefficient usage of a product is often visually apparent to a user as fluid staining occurs in only a limited area on the product. Such inefficient usage of a product may lead to consumer frustration, as a consumer may infer that the product failed to capture much waste, led to a leak, or at a minimum, did not provide sufficient value to justify the expense. Therefore, in the personal care area, numerous absorbent structures have been developed for efficiently utilizing larger areas of the absorbent portion of the articles. For example, multiple absorbent layered structures have been employed in articles (one layer stacked over another) to help transfer liquid or distribute liquid to larger areas of absorbent layers positioned beneath a liquid entry layer. However, in such layers, if structures with improperly matched capillary features or improperly placed superabsorbents are used, liquid may have a tendency to be blocked in movement in one or more directions, such as through gel blocking (for superabsorbent sheets) or misaligned capillary action, within density-gradient, layered structures. If such absorbent materials are not efficiently used, large areas of the absorbent article are devoid of waste at the time of article disposal, thereby failing to take advantage of the potential overall absorbent capacity of the article.
Despite various designs in the absorbent art, there is still a need for an absorbent article/product which when worn, takes full advantage of an absorbent structure to reduce leakage, and which is relatively thin and flexible for ease of wear in a consumer's undergarments. Such a thin and flexible product would also provide relative discreteness, an attribute that is also desired by consumers.
Even when article absorbent cores are functioning, such cores have a propensity to leak at certain locations on a product (depending on product type and user habits). Such leakage may cause frustrating and embarrassing staining of a user's under or even outergarments. While various systems have been developed to signal a user of an impending leak or saturation of an absorbent article, such signals are often conveyed using chemical or physical communications such as temperature change, scent change, print change upon product saturation or alternatively, embossment marker features. In such “signal” products, additional costly chemistries are needed to convey the message to the user, or alternatively, the user may have to remove the product, step off of the product, or out of the product, to see the signal. It therefore is desirable that “signal” products be developed by which a user could casually observe without use of additional chemistry (such as for example traditional “wetness indicator” technology), or product removal or special movements, so as to view a signal of impending leakage. There is also a need for feminine hygiene articles that allow a consumer the ability to see that such products are working throughout their lifecycle, so as to afford a sense of security and emotional comfort to the consumer.
Braided absorbent yarn-like materials have been used in connection with personal care articles, and such have been known to include superabsorbent polymers. However, use of such braided materials has been limited to specific projection-like structures for capturing moisture from crevices associated with a user's body. Such braided structures can for example, be seen in US20090312729 to Roche del Ayala and are positioned outside the main body of a personal care absorbent article.
Absorbent yarn materials have been described for use in personal care articles in conjunction with traditional absorbent sheets for retention of fluids. Such for example may be found in US20030088229 to Baker. However, such reference does not describe the use of superabsorbent yarns in-and-of themselves, as the sole basis of absorbent cores/portions of absorbent cores. Further, such reference relies on spatial channels between yarns to move fluid to the periphery of absorbent core structures.
Superabsorbent containing spun filaments (as opposed to yarn) in which superabsorbent is encapsulated by fluid permeable material, have been taught and suggested for use in personal care products. Such for example was disclosed in US20050130540 to Crane. While such filaments have been suggested for use in absorbent cores of personal care products, the use of such filaments have been described in sheet-like layers, which utilize large amounts of material in a non-targeted/inefficient fashion. Transport of such absorbent sheets is often cumbersome.
Absorbent sheets may also be stiff and subsequently add stiffness to the absorbent product. Such usage may be wasteful and expensive, and may impact a product's bulk, flexibility, and breathability, physical attributes that are of particular sensitivity to the women who use feminine hygiene products. In this regard, see also U.S. Pat. No. 6,458,456 to Zainiev and US20090054860 to Young et al.
It would be desirable to develop an absorbent article or an absorbent portion of an absorbent article that was flexible in use, that made efficient use of peripheral areas of the absorbent portion and which provided a signal or communication to the consumer of level of usage or saturation. In some absorbent articles it would be desirable to control flow of absorbed fluids to certain areas of an absorbent article, such as away from the transverse direction of an article, and in the longitudinal direction of the absorbent article. It is also desirable to have an absorbent article that could block or slow the flow of fluids to traditionally high risk leakage areas, such as in the wing or flap regions of child care products and feminine care hygienic pads/sanitary napkins.